Exercise, fasting, language... the secrets to a longer life: There's more to keeping healthy in your later years than laying off fatty foods, drinking less and giving up smoking. Catherine de Lange talks to experts in the ageing process and discovers that having a good marriage, regular fasting and learning languages are all beneficial to a longer and less stressful life: 'Fasting two days a week should have benefits'

Observer (UK)

JERRALD RECTOR, 26

LIFT WEIGHTS FOR BETTER IMMUNITY

By the time we reach 80, most of us will be infected with a type of herpes virus which erodes the immune system and takes years off your life without you even knowing it. PhD student Jerrald Rector, at the University of Birmingham, knows he has the bug, and is working on ways to keep it from doing harm.

What is this virus?

Cytomegalovirus - CMV - is a kind of herpes virus that is symptom-free and harmless until your immune system is challenged. The virus erodes the ability of your immune system to deal with other bugs throughout life. In the UK you have about a 1% or 2% chance of infection each year until you reach really old age. By the time we reach 80, about 85% of the population has the virus, so in addition to looking at ways to avoid catching it, I look at reactivation of the virus and its implications for the immune system itself. Once you have it, what do you do?

So you research what triggers the virus?

Yes. Basically the virus is really good at detecting when the immune system has its head turned. So when something like stress means that the immune system is preoccupied, the virus comes out of its dormant state and tries to make new viral parts and infect other cells. It takes a chunk out of the immune system by using up the repertoire of cells that you have that can fight against other things older people normally die of - fighting off this year's flu, for example. Any number of things can set off a reactivation.

What sort of things?

I look at psychological factors - anxiety, depression, exhaustion - as well as behaviours that have an impact on the immune system and might actually be able to control the virus.

What kinds of behaviours can keep the virus from reactivating?

One of the things that helps reactivate it is psychological stress. Obviously reducing stress is easier said than done but I personally use exercise as stress relief. I'm not a cardiovascular kind of guy so I channel my stress through resistance training and martial arts. I also try to control my diet and my sleep cycle. Sleep deprivation has been shown to have major effects on immune suppression - even two or three hours' decrease in sleep has an impact. So in my personal life I like to make sure I keep a regular amount of sleep to prevent weakening my immune system, to allow for less reactivation of the CMV.

And the exercise helps you de-stress?

Yes. Also, during my masters I found that aerobic exercise could be one way getting rid of cells that had become specific to fighting CMV, freeing up the immune system to fight other off other diseases.

As for diet, early research suggests that aspects of metabolism can aid in the replication of CMV, such as cholesterol. The virus takes over the host's cells and uses its own human machinery to create more viral parts. So what I also look at are lifestyle parameters that can affect the levels of things like cholesterol and glucose in the blood. For example, a well-balanced diet, combined with exercise, may lower the availability of these resources for CMV, and could help control its replication. So all in all, I try to regulate my sleep, exercise more and make sure that I'm trying to de-stress. Which is pretty hard while doing a PhD.

ANNA PHILLIPS, 36

FRIENDS HELP WITH STRESS

Dr Anna Phillips of the University of Birmingham studies how stress and depression affect your health, especially during ageing, and is discovering why a good set of friends can add years to your life.

What kinds of stressful events do you study?

In older adults we've shown that if you have a severe life stressor, such as bereavement, it can reduce your response to vaccination. This means you're not going to be able to fight off flu as well, or pneumonia, which are two of the biggest killers of older people. We have also found that long-term care-giving for a spouse with dementia has negative effects not just on vaccination response, but also on a whole range of different immune cells and how well they function.

We've recently also found that if you have a hip fracture and then go on to develop depression, not only does this affect how well you recover, but it also affects these immune cells and how well they function, which means you are more likely to get an infection and have slower physical recovery and more time in hospital.

How do relationships play into that?

As an example, in one study we found that people who were unhappily married had much lower response to the flu vaccine than people who were happily married.

How do relationships cause that kind of effect on the immune system?

We've got a few ideas. When you are suffering chronic stress you produce more of a stress hormone called cortisol. This in turn goes on to dampen down various parts of your immune system which are involved in fighting off infection and producing antibodies. These immune cells are really profoundly affected by your stress hormones. So people who have better social support and less stress in their lives seem to have healthier immune systems.

A happy marriage isn't always an option - any other tips?

You can mobilize your social support networks - that is, your close friends and family, in particular in periods when you are very vulnerable, for instance, after bereavement or a hip fracture. These are often times when you might be more socially isolated but these are the exact times when you need to start getting lots of support to help you deal with the negative consequences of stress. It will make you feel a bit better and will also have an impact on your physical function such as your immunity.

Is that what you do?

In the past couple of months I have gone through a lot of the things I research, including bereavement. I know that I'm at risk of infections so I'm trying to look after myself better and I'm mobilising a lot of social support.

Make sure you've got lots of friends at hand so you're not the only person dealing with it. I think a lot of that is having that set up before you're in difficulty. It's about having a sense of community - so for some people that's volunteer work, or going to a social or church group - meeting up with people with similar interests while you are still active and healthy and not too stressed, so you've got these resources later in your life when you're more likely to need them.

Can young people benefit too?

Definitely. It's more important when you're older because ageing itself has all of these same effects that stress has on the immune system. But even without the effects of ageing, stress can still have quite a profound effect. For instance, we have shown that healthy students with lots of stressful life events have poorer responses to vaccinations. So even when you're young you need to get your support in place to help you deal with these stressful situations.

JANET LORD, 56

RUNNING BOOSTS IMMUNITY

Janet Lord was a self-confessed couch potato when she got into running to lose weight. Now, as professor of immune cell biology at the University of Birmingham, and director of the MRC ARUK Centre for Musculoskeletal Ageing Research, she has discovered how running should also help her live longer.

So you run to stay young?

It didn't start off as something about ageing well, I started running in my early 30s because I was very overweight, had never done any exercise, and I decided to do something about it. I just got completely hooked on running and two years later I ran my first marathon. Then when I got into ageing research I realised that the benefits of being physically active extend beyond weight - it's really good for your heart, keeping muscles and bones strong, and it's clear now it is good for immune function as well.

How does running boost immune function?

We just completed a study where we were looking at how much physical activity older people do and at their immune systems, and we found that in older adults who don't take exercise, their neutrophils don't work as well. These are immune cells that help you fight bacterial infections such as hospital superbugs.

You also look at the effect of exercise on stress.

When you're in a stressed situation you have high levels of cortisol, and if it's raised for an extended length of time it has lots of negative effects that will have an impact on healthy ageing - things such as reducing your sensitivity to insulin, raising blood pressure, increasing muscle and bone loss, and it can affect your distribution of fat, so you lay more fat down centrally around the abdomen.

Certainly having high levels of cortisol is associated with shorter lifespan, so if you can lower those levels it's going to be beneficial, and exercise is one way to do that.

And do you know what kind of impact this can have on lifespan?

There's not enough data to give a precise number. The best data are on another aspect of ageing which is that as you get older, you have an increase in levels of inflammatory cytokines in your blood - molecules involved in the inflammatory response. And lower levels of inflammatory cytokines are associated with a longer life. So if you look at centenarians, they are amazing, they don't have this increase in inflammation; they seem to be protected, and they cope extremely well with the ageing process. And things like running lower your levels of these inflammatory cytokines as well.

Do people have to run?

No. Regular brisk walking is excellent, as is swimming. In fact running does impact on your joints so you do have to be careful. Also research has shown that resistance exercise, such as lifting weights, is especially good for maintaining good muscle strength and bone density as we age.

How often?

The research at Birmingham is now trying to find out exactly how much exercise an older adult needs. Some of the work shows that the older you are, the more exercise you need to do to get the benefits. And results are showing that as we get older we

might also need more resistance exercise - not necessarily lifting weights down the gym, but lifting a bottle of water, say.

Or a few press-ups?

That would do it but just going up stairs is even easier and great for muscles and bones.

SANDRINE THURET, 38

FASTING HELPS THE BRAIN

Dr Sandrine Thuret worked as a food scientist investigating 'exciting but not so important' science such as how to keep Froot Loops crunchy in milk, before training in neuroscience and ageing. She now combines those interests in her lab at the Institute of Psychiatry at King's College London, where she investigates how environmental factors, such as diet, can boost brain cells and improve memory.

What do you do to keep your brain young?

I eat every other day. Actually there are a few of us in the lab who do intermittent fasting. It's not that I eat nothing on a fasting day, but I'll grab a big latte and then maybe a bit later I'll have an apple and a cereal bar. Normally every other day I have busier, longer days, so it usually just happens by accident, as I don't have time for lunch and then I get home too late for dinner. The other days I eat normally.

What happens to our brain cells as we age?

Until the 1990s people thought that adults couldn't generate new brain cells, but now we know there is a small area in the adult brain called the hippocampus which is involved in memory and mood, where, in adults we can make new brain cells. These brain cells, or neurons, have a very important role in learning and memory. As we age we make fewer and fewer of these new cells. In my lab we are interested in understanding how they are formed and how we can promote their growth, and we have found that diet and exercise both have an effect.

What are the benefits of having more of these new brain cells?

I definitely think that we may be able to prevent cognitive decline during ageing through neurogenesis - this process of having newborn neurons in the hippocampus.

And we have recently found that neurogenesis is involved in Alzheimer's disease. We suspect that if we could prevent the loss of new neurons in the hippocampus before the onset of the disease, we may be able to modify or delay its appearance.

What kinds of things make a difference?

Because of my background in food science one of the approaches I have in my lab is looking at the effect of diet on neurogenesis and how this will impact on memory. One diet we've been doing a big study on is intermittent fasting.

So what's the effect of fasting?

For now we are looking at neurogenesis in mice, and then the idea is to move to human intervention studies. There were already studies showing that restricting calories quite dramatically will increase neurogenesis in mice, but we don't know whether that would be feasible for everyone in everyday life.

When we did that here with our mice we found that they were really greedy the next day and ate almost double - so over two days we would restrict their calorie intake only by 10% - which is very low and feasible for anyone. And what we found is that the effect is not actually due to the calorie restriction itself but due to the fact they were eating every other day.

How immediate is the effect?

In mice that have poor cognition, they can go on intermittent fasting for three months and we see differences in their memory that are linked to neurogenesis.

There has already been some research showing that in people over 70, intermittent fasting led to a 30% improvement in verbal memory after three months, which is quite dramatic. We now want to find out whether this was due to neurogenesis and we're planning our own studies on humans.

Why does fasting have this effect on the brain?

You are putting a mild stress on the brain, and it could be that this is left over from our primal years where there was no food - so we had to increase our number of neurons to search for food more efficiently.

A lot of people now fast two days a week. Would you expect the same effects as every other day?

If you have only a little bit of food every day, this is not going to happen, but if you put your brain under that mild stress two days a week, it should have some benefits, absolutely.

THOMAS BAK, 52

LANGUAGES COMBAT DEMENTIA

Thomas Bak speaks more than six languages. As a cognitive neurologist at the University of Edinburgh, his research is now revealing how bilingualism can help keep dementia at bay.

What kinds of things have you been looking at?

Past research has shown that bilingual people who get Alzheimer's disease tend to get it four or five years later than monolingual people. These studies were done in Canada where bilinguals are usually immigrants, so you have a lot of what we call confounding variables - people will have different ethnic backgrounds, lifestyle, diet and so on. I am doing studies along with my colleague Suvarna Alladi in Hyderabad, in India, which is one of the biggest multilingual countries in the world. We are looking at more than 600 patients with different types of dementia who are either bilingual or monolingual, and practically none of them are immigrants. So we get rid of the confounding variable of immigration and we get the same results. It's not that bilingualism prevents dementia - people will get it anyway - the point is on average it will be delayed by four or five years.

Where does this protective effect of language come from?

There are different theories but the most popular is that bilingualism is a kind of permanent experience of switching between languages and suppressing the one you aren't using. Doing this offers you practically constant brain training. It's much cheaper than a lot of brain training sets you can buy, it's certainly socially more enjoyable, but it forces your brain to train permanently - and that could be the reason why you have such differences in dementia.

What about forms of dementia other than Alzheimer's?

We are doing the first study looking at three different types of dementia, and so far we find the same thing independently in each one.

Do you have to learn languages as a child to get the benefits?

We are doing research at the moment that suggests you get advantages in both early and late language acquisition, but there might be slight differences in the type of cognitive processes that are affected. But both of them have a beneficial effect against dementia.

And do you have to be perfectly bilingual?

For a long time studies of bilingualism looked at children who grow up with one parent speaking one language and the other parent speaking another language, with the child growing up perfectly fluent in both languages. The problem is that this does not reflect the vast majority of bilingual people in the world.

In reality, people might learn one language after the other, they might not reach absolute fluency in one, or will be used to using them in different contexts. It's less clean and more real. In our India studies we were looking at these kinds of people, so it looks like you don't have to be perfectly bilingual.

One thing we don't know is how much you have to practise. My favourite metaphor is that the fact you can swim will not necessarily prevent you from having a heart attack, but if you go swimming three times a week it might - so in this case it's not the ability itself, but the use of the ability. With language, we don't have enough data to know for sure which it is.

Is more languages better?

We are working on this question as well and there have been mixed results, so the jury is still out. It might be more to do with how often you switch between languages, rather than how many different languages you speak.

Are these findings your motivation for speaking so many languages?

When I was growing up there was a lot of prejudice - people thought that if a child was brought up with two languages it would end up schizophrenic. So my mother was very reluctant for me to learn her native tongue - German - when I was growing up in Poland. Then I lived in different countries and my PhD was on language disorders, so this is how I came into it. I now use four languages more or less on a daily basis. I speak Polish with my daughter, German with family and friends, English at work, and my wife is Spanish.

So, it was not that I learned languages because I thought it would be good against Alzheimer's - it was my passion. But now, working on bilingualism, I find it deeply reassuring, and we are trying to bring up our daughter to be trilingual. It's not an extra effort for the kids, and it might well be beneficial, so I think there is nothing to lose.

Captions:

Anna Phillips: 'People who have better social support and less stress in their lives seem to have healthier immune systems.' Photograph by Gary Calton

Jerrald Rector: 'Sleep deprivation has been shown to have major effects on immune suppression - even two or three hours' decrease in sleep has an impact.' Photograph by Jonas Briels

Janet Lord: 'High levels of the hormone cortisol are associated with shorter lifespan. Exercise is one way to lower those levels.' Photograph by Andrew Fox

Sandrine Thuret: 'Research has shown that in people over 70, intermittent fasting led to a 30% improvement in verbal memory after three months.' Photograph by Karen Robinson

Thomas Bak: 'I use four languages more or less on a daily basis: Polish with my daughter, German with family and friends, English at work - and my wife is Spanish.' Photograph by Murdo MacLeod